"compared to Trumps gaffs its insignificant" - it is significant - and in some ways rather more racist than what Trump has said, because it shows a complacency that is at the root of the reasons African Americans are among the least privileged in US society. Part of the reason Biden made the statement is that Trump - oddly enough - has actually done far more for the African American community than most presidents have done for years. Then again Trump has to work to win their vote. Biden evidently doesn't think he has to.
But it's not an own goal, because Biden could be a mass murderer and the US media would find an excuse for his actions. No doubt it will be used by Trump's campaign in advertising, but Biden will still get 80% of the African American vote. Only 18% of US voters are independents - all the rest are registered with one or other of the parties. The challenge for both candidates is to get enough independents to vote for them in swing states to win electoral college votes.
The US has, yet again, a terrible choice of candidates for the next election. However bad Trump may be on everything else on the economy he's more or less Ok. Biden on the other hand may be palatable on many issues but would be catastrophic for the US economy, and even some Democrats admit he doesn't always seem to have his brain in gear. Two old white guys over 70, one of whom makes the most ridiculous statements and the other that has no clue what he's saying half the time. Take your pick as to which is which.